Insulating separator for storage battery

Abstract

The invention relates to a separator (1) suitable for separating two cells (2) of a battery (3), for example of an electric or hybrid electric vehicle, said separator (1) comprising at least one insulating layer comprising a composite material (4) comprising a binder mixed with aerogel particles (5), the volume content of the aerogel particles (5) in the composite material (4) is greater than 20%, and the binder is of mineral type. The invention also relates to a battery comprising a separator according to the invention, and to a method for producing a separator according to the invention.

Description

[0001] The present invention belongs to the field of storage batteries. More specifically, the present invention relates to a unit separator for a storage battery.

[0002] Due to the advantages of low CO 2 emissions, electric and hybrid electric vehicles are undergoing significant development. These vehicles are equipped with batteries, usually lithium-ion type batteries. These batteries sometimes experience thermal runaway, during which the temperature inside the battery rises spontaneously. The battery can then heat up until it catches fire or explodes. Therefore, managing this risk is an important safety issue. One of the challenges is to limit and / or slow down the spread of heat and / or fire between adjacent battery cells.

[0003] Document WO2006137935 discloses a thermal insulation separator that can be arranged between the cells of a battery. It includes a fiber-reinforced aerogel encapsulated in a polymer. This solution is very expensive and performs poorly in terms of thermal insulation.

[0004] The object of the present invention is to provide an insulating separator with improved thermal insulation, fire resistance, and durability.

[0005] An object of the present invention is to provide a highly compressible, thermally insulating, and electrically insulating separator.

[0006] A further object of the present invention is to provide a simple, multi-performance insulating separator that is composed of a single component that is easy to integrate into existing batteries.

[0007] The object of the present invention is to at least partially respond to the above objects by proposing a separator mainly composed of an adhesive (for mechanical strength) and an aerogel (for thermal insulation and fire resistance). For this purpose, a separator suitable for separating two cells of a battery (such as a battery of an electric or hybrid electric vehicle) is proposed, the separator including at least one insulating layer, the at least one insulating layer including a composite material, the composite material including an adhesive mixed with aerogel particles, preferably, the volume content of the aerogel particles (5) in the composite material (4) is greater than 20%, and the sum of the weight contents of the aerogel particles and the adhesive in the composite material (4) is greater than 80%; the adhesive used is a mineral-type adhesive.

[0008] Due to these provisions, the rate of heat and / or fire propagation between two battery cells can be reduced, and the risk of fire spreading outside the battery or the battery exploding can be reduced. In addition, this solution has good durability because the stress applied to the battery does not damage the separator; this solution is simple to manufacture. In addition, this type of mineral adhesive enables a paste to be made with a higher proportion of aerogel. Therefore, the weight is further reduced, but more importantly, the thermal conductivity is reduced because it is closer to the thermal conductivity of the aerogel.

[0009] According to a further feature:

[0010] - The separator may comprise at least one additional layer which is deformable at any square area of greater than or equal to 4 cm2 on one of its outer faces so as to absorb at least part of the volume reduction of the separator and thus prevent wear of the battery cell due to cell swelling.

[0011] - At least one of the at least one additional layer may comprise at least one layer of ceramic fiber paper, which is a simple and robust way of implementing the present invention.

[0012] - At least one of the at least one additional layer has a three-dimensional shape on at least one of its faces, for example in the form of a honeycomb, which is a simple solution for implementation and enables the production of a separator with improved durability.

[0013] - The insulating layer may comprise at least one mechanical reinforcement element, for example in the form of a honeycomb.

[0014] This ensures that the layer remains in place, for example when the adhesive tends to break.

[0015] - The adhesive may comprise a mineral material, such as calcium hydroxide, the volume content of the aerogel particles in the composite material being greater than 90%, and the weight content of the mineral material in the adhesive being greater than 50%, which is a solution for reducing the weight of the separator and obtaining a particularly interesting thermal conductivity.

[0016] The present invention also relates to an electric or hybrid electric vehicle battery comprising at least two cells and at least one insulating separator according to the invention arranged between the cells.

[0017] Thanks to these measures, the rate of heat and / or fire propagation between two battery cells can be reduced, and the risk of fire spreading outside the battery or of the battery exploding can be reduced. In addition, this solution has good retention over time and the stress applied to the battery does not damage the separator; the separator is easy to manufacture.

[0018] Finally, the present invention relates to a method for manufacturing an insulating separator according to any one of claims 1 to 5, the method comprising the following steps:

[0019] - Manufacturing aerogel particles.

[0020] - Mixing the aerogel particles with the liquid adhesive.

[0021] - Curing the obtained mixture in a mold to obtain the composite material.

[0022] Due to these arrangements, the separator according to the present invention can be produced in a simple manner.

[0023] According to a further feature:

[0024] - Manufacturing the aerogel may include the following sub-steps:

[0025] - Mixing a precursor with a synthesis solvent and a hydrolysis agent such as water and optionally a catalyst to obtain a gel,

[0026] - Granulating the obtained product by jet-cutting the gel to obtain granules,

[0027] This results in fewer angular granules that are less brittle and less likely to break up,

[0028] - Manufacturing the aerogel may include the following sub-steps:

[0029] - Drying the granules, which is carried out entirely at a pressure above the critical point of CO 2 2.

[0030] This avoids damaging the aerogel granules and produces a hydrophilic aerogel,

[0031] - Manufacturing the aerogel may include the following sub-steps:

[0032] - Mixing a precursor with a synthesis solvent and a hydrolysis agent such as water and optionally a catalyst to obtain a gel,

[0033] - Granulating the obtained product to obtain granules,

[0034] - Keeping the granules in contact with the synthesis solvent and the hydrolysis agent,

[0035] - Washing the granules with a washing solvent to extract the hydrolysis agent and, where appropriate, the catalyst,

[0036] - Drying the granules to extract the synthesis solvent and / or washing with an excess of supercritical CO 2 2.

[0037] The granulating, keeping, washing and drying sub-steps are carried out at a pressure above the critical point of CO 2 2, and these conditions are maintained between these steps so that the aerogel can be continuously manufactured; due to the reduction of dangerous state changes and decompression steps, the manufacturing time and cost are significantly reduced, and the product quality is improved.

[0038] The present invention will be better understood by reading the following detailed description and referring to the accompanying drawings, in which:

[0039] Figure 1 is a schematic cross-sectional view of a battery including a separator according to the present invention.

[0040] Figure 2 is a schematic cross-sectional view of a separator according to the present invention.

[0041] In Figure 2 the preferred embodiment shown in Figure 1 the separator 1 according to the present invention is intended to be integrated between the cells 2 of a battery 3, as

[0042] shown. In the battery 3, the separator 1 can be arranged between all adjacent cells 2, thus achieving maximum efficiency in preventing the spread of heat or fire in the battery. Alternatively, in order to achieve a smaller battery, for example, the separator 1 can be arranged between groups of cells 2, and for example, the separator 1 is placed every two or three cells 2.

[0043] The shape and size of the separator can vary according to the application.

[0044] The size of the face of the cell 2 adjacent to the separator is, for example, 200×100 mm or 300×100 mm. Then, the separator is preferably in the shape of a cuboid of these dimensions.

[0045] The thickness of the separator can be, for example, between 2 mm and 4 mm, making it suitable for a wide range of applications.

[0046] The present invention can be applied to any battery, especially batteries that require thermal management and batteries that undergo cell swelling.

[0047] The present invention is particularly suitable for the batteries of electric or hybrid electric vehicles. An electric vehicle is a vehicle whose propulsion is ensured only by one or more electric motors, and a hybrid electric vehicle is a vehicle that includes one or more electric motors capable of ensuring vehicle propulsion and one or more other types of motors (usually thermal motors) capable of ensuring vehicle propulsion.

[0048] The present invention can also be applied to hydrogen vehicle batteries.

[0049] Finally, the present invention can be applied to domestic batteries, for example, used to store the electricity generated by solar panels.

[0050] The battery 3 is preferably a lithium-ion battery. This type of battery is widely used today due to its performance in terms of autonomy and its low cost. However, it is also particularly prone to thermal runaway.

[0051] The vehicle can be of any type, including cars, trucks, vans or motorcycles.

[0052] The separator according to the present invention comprises at least one insulating layer. The insulating layer comprises a composite material 4 which comprises an adhesive mixed with aerogel particles 5.

[0053] The adhesive keeps the aerogel 5 particles optimally distributed within the separator.

[0054] The separator 1 preferably complies with the UL 94V0 standard for flame retardancy.

[0055] The separator 1 preferably has heat resistance such that it can withstand two minutes with one side at 800 °C and the other side remaining below 150 °C.

[0056] The separator 1 preferably has heat resistance and flame retardancy such that it can withstand ten minutes with one side at 1400 °C and in the presence of a flame, and the other side remaining below 300 °C.

[0057] The size of the aerogel 5 particles is between 0.015 mm and 3 mm.

[0058] The aerogel 5 can be a hydrophobic or hydrophilic aerogel.

[0059] Preferably, the aerogel is hydrophobic.

[0060] The aerogel 5 can be based on any material relevant to the application. For example, it can be a silica aerogel, a silica-polymer hybrid aerogel, a carbon aerogel or a mixture of some of these aerogels.

[0061] The aerogel 5 is preferably a silica aerogel which is a very good thermal insulator and has a thermal conductivity of, for example, approximately 0.012 W / m.K. The silica aerogel can be made, for example, from raw materials in which more than 75% by weight is recycled material from the demolition industry, thus reducing the manufacturing cost and energy consumption required for the manufacturing raw materials.

[0062] The adhesive can be a mineral, i.e. it comprises at least 50% by weight of mineral material in the adhesive. An example is calcium hydroxide which has the advantage of being light in weight. In addition, such an adhesive enables a paste to be made with a higher proportion of aerogel. Thus, the weight is further reduced, but most importantly the thermal conductivity is reduced because it is closer to the thermal conductivity of the aerogel.

[0063] In some embodiments, the insulating layer may include a reinforcing element, for example in the form of a honeycomb, such as the "Nomex Honeycomb" product (registered trademark) sold by the DuPont company, which is made of paper covered with phenolic resin. Different types of matrices may be used among the different materials (such as ceramic paper) that a person skilled in the art will know how to select. Such reinforcing elements are of particular interest when the binder (such as a binder of mineral type) has a tendency to break.

[0064] The volume content of the aerogel particles 5 in the composite material 4 is greater than 20%, imparting good thermal insulation to the composite material 4.

[0065] The binder and the aerogel particles 5 constitute most of the composite material 4. In particular, the sum of the weight contents of the aerogel particles 5 and the elastomer in the composite material 4 is greater than 80%, preferably greater than 90%. In addition to the binder and the aerogel particles 5, the composite material 4 may also contain various additives, such as surfactants, to optimize the distribution of the aerogel particles 5 in the composite material 4.

[0066] The separator 1 may further include at least one additional layer 6. The volume of the cells 2 of the battery 3, and in particular their thickness, may vary during the charge / discharge cycle. Since the battery pack including the cells 2 and the separator 3 has a constant volume, the separator 3 must be able to cope with the reduction in the volume allocated to them. When the volume of the separator 1 decreases, the additional layer 6 is configured to limit the pressure buildup inside the composite material 4, particularly at the aerogel particles 5 which are at risk of rupture under the action of high pressure. The additional layer 6 is described in more detail below.

[0067] In a particular embodiment, the separator 1 includes two additional layers, one additional layer on each side of the insulating layer.

[0068] In other embodiments, the separator 1 includes an additional layer disposed between two insulating layers.

[0069] The additional layer 6 is capable of deforming to absorb the reduction in the volume of the separator 1. In order to achieve efficiency over the entire surface of the separator 1, the additional layer 6 is capable of deforming at any square area greater than or equal to 4 cm2 on one of the outer faces located in its outer face.

[0070] In a preferred embodiment of the present invention, the additional layer 6 comprises at least one layer of ceramic fiber paper. Examples include EST C30 or EST C310 sold by Morgan Advanced Materials. The ceramic fiber paper can be applied, for example, by gluing or laminating to one side of the insulation layer, or to both sides, i.e., between the insulation layer and the walls of the cells 2 on either side of the separator 1. This ceramic fiber paper layer absorbs the volume reduction caused by the reduced thickness of the separator 1, and the volume reduction of the insulation layer is small or non-existent. The ceramic fiber paper layer can be about 1 mm thick.

[0071] The additional layer 6 can also comprise at least one layer of elastomer, such as a silicone elastomer.

[0072] The additional layer 6 can also include a silicone foam, such as the silicone foam sold by Saint-Gobain under the trade name Norseal (registered trademark).

[0073] In another embodiment, the additional layer 6 has a three-dimensional shape. Such a layer can be made of an elastomer. The shape is then characterized by compression zones; for example, the shape can be a honeycomb shape, and the edges formed by hexagons constitute the compression zones. These compression zones make it possible to absorb the volume change of the separator 1 by deforming a part of the separator 1, while the rest of the separator 1 can maintain a volume close to its initial volume. For example, the edges of the hexagons widen in a plane perpendicular to the force, so that the thickness of the separator 1 can be reduced without a significant increase in pressure. The additional layer 6 can be directly molded or cast into a shape characterized by compression zones.

[0074] The different types of additional layer 6, namely ceramic fiber paper, elastomer, silicone foam or three-dimensional shape, can be used alone or in combination.

[0075] The separator 1 according to the present invention can include a protective envelope, such as PET, to protect its insulation and volume reduction management layers. This protection is particularly useful when the adhesive is a mineral type that tends to break.

[0076] The present invention also relates to an electric or hybrid electric vehicle battery 3, which comprises at least two cells 2, and at least one insulating separator 1 arranged between said cells 2.

[0077] Finally, the present invention relates to a method for manufacturing the separator 1, which comprises the following steps:

[0078] - manufacturing aerogel particles,

[0079] - mixing the aerogel particles with said adhesive (for example, calcium hydroxide). The adhesive can be dissolved in a solvent,

[0080] - Curing the resulting mixture in a mould to obtain said composite material.

[0081] Parts, such as a structured matrix in the shape of a honeycomb, can be added to the mold.

[0082] This can be achieved, for example, by increasing the temperature, adding a catalyst or evaporating the solvent.

[0083] Example

[0084] To prepare a separator according to the invention, 14.19% by weight of calcium hydroxide was mixed with water. Next, 85.8% by weight of hydrophobic silica aerogel (sieved particle size between 15 microns and 3000 microns and density of 70 kg / m3) and 0.01% by weight of sunscreen were added and mixed for 10 minutes. The result was a homogeneous composition with the consistency of a paste. The paste was spread on a honeycomb plate. The paste was dried in the plate at a temperature of 35°C for 10 hours. The result was an insulating separator having the following characteristics:

[0085] Apparent density of dried paste: 160kg / m3

[0086] Density of partition (paste + board): 240kg / m3

[0087] Thermal conductivity of dried paste: 18mW / mK at 20°C

[0088] Thermal conductivity of separator (paste + plate): 23mW / mK at 20°C

[0089] In the above example 1, almost pure calcium hydroxide was used as a binder. Alternatively, a commercially available mixture of about 30% calcium hydroxide with other minerals can be used as a binder, in which case the binder mass is slightly increased, for example to 25% (based on the mass of such binder) instead of 14.19%.

[0090] Depending on the thickness of the separator, in particular between 1 mm and 4 mm, the drying temperature may vary between 20° C. and 50° C., and the drying time between 4 hours and 24 hours.

[0091] Depending on the type of aerogel used (and in particular its density, which can vary between 50 and 150 kg / m3), the binder used (almost pure calcium hydroxide or a mixture of mineral materials) and the board used, the density of the composite material can vary between 120 and 300 kg / m3.

[0092] Depending on the shape and density of the plates used, whether honeycomb-shaped or not, a relatively low aerogel-to-separator volume content can be achieved, preferably higher than 20%, to utilize the insulating properties of the aerogel; thin, low-mass plates can also be used to achieve an aerogel-to-separator volume content of more than 80%; in some cases, more than 90% or even 99% (by volume) for particularly good results.

[0093] The obtained paste can also be placed in a mold to dry, thereby obtaining a composite material that can be used in the separator according to the present invention without adding honeycomb plates. The result is a separator in which the aerogel content can far exceed 90% (by volume).

[0094] Other examples were tested:

[0095] ● Mix 7.5% (by weight) of calcium hydroxide with 92.5% of aerogel with a density of 50 kg / m3 to produce a paste with a density of 140 kg / m3.

[0096] ● Mix 3.7% (by weight) of calcium hydroxide with 96.3% of aerogel with a density of 90 kg / m3 to produce a paste with a density of 166 kg / m3.

[0097] ● Mix 2% (by weight) of calcium hydroxide with 98% of aerogel with a density of 150 kg / m3 to produce a paste with a density of 207 kg / m3.

[0098] The obtained thermal conductivity is similar to that obtained in the above examples.

[0099] When manufacturing aerogel particles, the above method may include the following sub-steps:

[0100] - Mix a precursor with a synthesis solvent and a hydrolysis agent such as water and optionally a catalyst to obtain a gel,

[0101] - Granulate the obtained product by cutting a jet of the gel to obtain particles.

[0102] For example, the gel passes through an opening whose size corresponds to the desired particle size. The jet formed at the outlet of the pore diameter is then cut at a frequency that also depends on the particle size.

[0103] Jet cutting granulation produces aerogel particles with a relatively regular shape and few corners. This reduces the risk of the aerogel particles 5 cracking or splitting once integrated into the separator 1, especially under the action of stress caused by the expansion of the cells 2 of the battery 3.

[0104] When manufacturing aerogel particles, the method for manufacturing the separator 1 may include the following sub-steps:

[0105] - The granule drying is carried out entirely at a pressure above the CO 2 critical point.

[0106] On the one hand, this type of drying avoids the deterioration of the granules during drying, and on the other hand ensures that the aerogel granules remain hydrophilic. In fact, other types of drying, involving for example an evaporation step in ambient air, can lead to the loss of the hydrophilic properties of the aerogel granules.

[0107] Finally, when manufacturing the aerogel granules, the method for manufacturing the separator 1 can be a continuous method known to those skilled in the art and described in the document FR1670366. This method comprises the following steps:

[0108] - Mixing a precursor with a synthesis solvent and a hydrolyzing agent such as water and optionally a catalyst to obtain a gel,

[0109] - Granulating the obtained product to obtain granules,

[0110] - Keeping the granules in contact with the synthesis solvent and the hydrolyzing agent,

[0111] - Washing the granules with a washing solvent to extract the hydrolyzing agent and any catalyst,

[0112] - Drying the granules to extract the synthesis solvent and / or washing with an excess of supercritical CO 2 performing the granulation, keeping, washing and drying sub-steps at a pressure above the CO 2 critical point, and maintaining these conditions between these steps.

[0113] Due to these provisions, the aerogel manufacturing method can operate continuously, where pressure build-up occurs at the stage where the product is still fluid. Once the product is solid (i.e., after granulation), it is no longer possible to continuously build up pressure. Thanks to the present invention, once the product is solid, the product does not require any pressure build-up, and apart from the final decompression, the product does not require decompression either. This significantly reduces the production time and cost, and improves the product quality by reducing the number of risky state changes and decompression steps. In addition, the method enables the drying step to be carried out entirely at a pressure above the CO 2 critical point without increasing the cost.

[0114] In this continuous method, the following features can be achieved:

[0115] - The mixing stage can also be operated at a pressure above the CO 2 critical point, so that this stage can be slightly accelerated,

[0116] - During the drying step, at a condition such that CO 2At temperature and pressure conditions where the supercritical and solvent-laden particles are heavier than the CO-laden particles, subject the solvent-laden particles to a supercritical CO jet to place them under fluidized bed conditions, enabling the drying step to be carried out continuously and accelerating the drying step. 2 The jet of CO 2 is used so that the drying step can be continuously performed and accelerated.

[0117] - The synthesis and / or washing solvent can be an organic solvent, and the drying step can be carried out at a pressure between 100 bar and 200 bar and a temperature between 35 °C and 50 °C. Ethanol is an inexpensive product suitable for this method, and the conditions between 100 bar and 200 bar and between 35 °C and 50 °C

[0118] mean that at certain CO injection rates into the fluidized bed, the particles containing ethanol do not fly out, while only the particles containing supercritical CO 2 fly out at the top of the column. 2 The particles containing only supercritical CO

[0119] can be recycled for the rest of the method.

[0120] - After the drying step, the method for manufacturing the aerogel can include replacing the supercritical CO with an inert gas, preferably nitrogen. 2 Subsequently, a pressure reduction step is carried out, preferably in stages. This additional step enables rapid pressure reduction without damaging the aerogel particles.

[0121] - During the step of replacing the supercritical CO with an inert gas, 2 under temperature and pressure conditions where the CO 2 is supercritical and the charged particles of supercritical CO 2 are heavier than the charged particles of the inert gas, the particles filled with supercritical CO 2 can be subjected to a jet of the inert gas to place them under fluidized bed conditions, enabling the step of replacing the supercritical CO with the inert gas 2 to be carried out continuously and accelerating this step.

[0122] The continuous method for manufacturing aerogel particles can be implemented in a factory for manufacturing particulate aerogel from precursors. The factory includes:

[0123] - A mixing reactor

[0124] - Granulation equipment that can form particles from a jet of gelling liquid from the mixing reactor. The granulation equipment may be located inside the aging reactor.

[0125] - An aging reactor

[0126] - A washing reactor

[0127] - Drying equipment,

[0128] - Pressure reduction equipment.

[0129] The special feature of this device is that the aging reactor, washing reactor and drying reactor, as well as the components for transferring products between these reactors, are configured to operate at a pressure above the critical point of CO 2 and enable the product to be retained from one reactor to another.

[0130] Due to these features, this plant can continuously produce aerogel particles while pressure can be applied at the stage when the product is still fluid.

[0131] The following features can be used in this device:

[0132] - The mixing reactor can also be configured to operate at a pressure above the critical point of CO 2 and retain the product from one reactor to another; this enables further reduction of the reaction time.

[0133] - This plant can also include a first fluidized bed column configured to enable the solvent contained in the particles to be replaced by supercritical CO 2 so as to enable drying of the particles and acceleration of the drying stage.

[0134] - This plant can also include a second fluidized bed column configured to enable the supercritical CO 2 contained in the particles to be replaced by a pressurized inert gas (preferably nitrogen), so as to enable rapid pressure reduction without damaging the aerogel particles.

[0135] Although the above description is based on specific embodiments, it in no way limits the scope of the present invention and can be modified, especially by substitution of technical equivalents or by different combinations of all or some of the features developed above.

Claims

1. A separator (1) suitable for separating two cells (2) of a battery (3) of an electric or hybrid electric vehicle, for example, the separator (1) comprising at least one insulating layer, the at least one insulating layer comprising a composite material (4), the composite material (4) comprising an adhesive mixed with aerogel particles (5), the adhesive and the aerogel particles (5) representing the main part of the composite material (4). Characterized in that the adhesive is of a mineral type, in particular, the adhesive comprises a mineral material, and the weight content of the mineral material represents at least 50% of the adhesive.

2. The separator (1) according to the preceding claim wherein the volume content of the aerogel particles (5) in the composite material (4) is greater than 20%.

3. The separator (1) according to one of the preceding claims wherein the sum of the weight contents of the aerogel particles (5) and the adhesive in the composite material (4) is greater than 80%.

4. The separator according to one of the preceding claims, the separator comprising at least one additional layer (6), the at least one additional layer (6) being deformable at the level of any square region having an area greater than or equal to 4 cm2 on one of its outer faces so as to absorb at least a part of the volume reduction of the separator.

5. The separator according to one of the preceding claims wherein at least one of the at least one additional layer (6) comprises ceramic fiber paper.

6. The separator according to one of the preceding claims wherein at least one of the at least one additional layer (6) has a three-dimensional shape on at least one of its faces, for example in the form of a honeycomb.

7. The separator according to one of the preceding claims wherein the insulating layer comprises at least one mechanical strengthening element, for example in the form of a honeycomb.

8. The separator according to one of the preceding claims wherein the adhesive comprises at least 30% calcium hydroxide.

9. The separator according to the previous claim wherein the adhesive comprises at least 50%, preferably at least 80%, calcium hydroxide.

10. The separator according to one of the preceding claims wherein the volume content of the aerogel particles (5) in the composite material (4) is greater than 90%.

11. An electric or hybrid electric vehicle battery (3), the battery comprising at least two cells (2) and at least one separator (1) according to one of the preceding claims arranged between the cells (2).

12. A method for manufacturing a separator (1) according to one of claims 1 to 10, the method comprising the following steps: - manufacturing aerogel particles (5), - mixing the aerogel particles (5) with the liquid adhesive, - curing the resulting mixture in a mold to obtain the composite material (4).

13. The manufacturing method according to the previous claim wherein manufacturing the aerogel particles (5) comprises the following sub-steps: - Mix a precursor with a synthesis solvent and a hydrolysis agent such as water and optionally a catalyst to obtain a gel, - Granulate the obtained product by means of a jet of the gel to obtain granules.

14. The manufacturing method according to one of claims 12 to 13, wherein, Manufacturing the aerogel granules (5) comprises the following sub-steps: - The granule drying is carried out entirely at a pressure above the CO 2 critical point.

15. The manufacturing method according to the previous claim, wherein, Manufacturing the aerogel granules (5) comprises the following sub-steps: - Mix a precursor with a synthesis solvent and a hydrolysis agent such as water and optionally a catalyst to obtain a gel, - Granulate the obtained product to obtain granules, - Keep the granules in contact with the synthesis solvent and the hydrolysis agent, - Wash the granules with a washing solvent to extract the hydrolysis agent and any catalyst, - Dry the granules to extract the composition and / or wash with an excess of supercritical CO 2 to wash the solvent Operating the granulation, holding, washing, and drying sub-steps at a pressure above the critical point of said CO 2 and maintaining these conditions between these steps.

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